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(No Model.) 3 Sheets-Sheet 1. G. M. CLARK. HARROW.

No. 466,771. Patented Jan. 12,1892.

(No Model.) 3 Sheets-Sheet 2.

G. M. CLARK. HARROW.

No. 466,771. v Patented Jan. 12, 189 2.

(No Model.) 3 Sheets-Sheet 3.

- G. M. CLARK.

HARROW.

N0". 466,771. Patented Jan. 12, 1892.

UNITED STATES PATENT OF ICE.

GEORGE MARSHALL CLARK, OF HIGGANUM, CONNECTICUT, ASSIGNOR TO CLEMENT S.HUBBARD, OF SAME PLACE.

HARROW.

SPECIFICATION forming part of Letters Patent No. 466,7? 1, dated January12, 1892. Application filed April 23, 1889. Serial No. 308,295- (Nomodel.)

To all whom it may concern.-

Be it known that I, GEORGE MARsnALL CLARK, of I-Iigganum, in the countyof Middlesex and State of Connecticut, have invented certain new anduseful Improvements in Harrows; andIdo hereby declare that the followingspecification, taken in connection with the drawings furnished andforming a part of the same, is a clear, true, and complete descriptionof the several features of my invention.

- Harrows embodying my said improvements pertain to that class ofmachines in which soil-working devices are revolved; but the characterof said devices may be widely varied without departure from myinvention. It is well known that various soils, crops, and weeds requiremore or less radical variations in the form and operation of thesoil-working devices for securing the best results in each case, andhence I employ many forms of disks, such as the plain, concavo-convex,corrugated, bladed and toothed, and also starwheels of various forms,according to the particular duty for which my harrow may be intended.

A harrow embodying my invention essen tially embodies two gangs ofrotative soilworking devices, one in front of the other, a frame whichis supported upon both of said axles, and a pole which is adjustablerigidly with relation to said frame, so that the entire weight of theframe-pole (and adriver, if desired) may be borne wholly by the frontaxle, or partially by both axles, according to adj ustment, thusenabling wide variation in capacity for service. For aifording stillfur- .ther capacities the two gang-axles are geared It is to beunderstood that my invention does not relate to that class of machinesin which one or more sets of rotative soil-working devices are suspendedin hanger-frames from main frames which are supported on the axles ofcarrying-wheels or on rollers,

'and the other gang operate as clearers.

spikes, and which serve also as means for driving the rotativesoil-working devices.

Referring to the drawings, Figures 1 and 2 illustrate in side elevationand in top or plan view one of my novel harrows embodying all of thefeatures of my invention in a desirable form. Fig. 3 illustrates in sideview one of my harrows adjusted so that one gang of soilworking deviceswill operate upon the soil Fig. 4 illustrates in top or plan View one ofmy harrows in which the gang-axles are inclined to the line of draft,instead of being at right angles thereto, as in Fig. 2. Fig. 5 in sideview illustrates one of my harrows in which :the gangs are geared tooperate at the same speed. Fig. 6 illustrates the harrow-frame and itspole arranged to admit of only two adjustments of the gangs. Figs. 7 to1'0 illustrate some other of the various forms of soilworking devicessuitable for use in my harrows, according to the character of workintended.

In the harrow shown in Fig. 1 there are two gangs of rotati'vesoil-working devices, re spectively mounted upon and rotatable withtheir axles a, and h. In this instance said devices are thin twistedsteel plates, substantially alike in both gangs, although the plates 0and c on the axle a are coupled together in pairs. The plates 0 on theaxle b are mounted singly thereon, but are varied in their axialrelations to the axle, and they are of such length and are so arrangedthat their ends as they revolve intermittingly, occupy the spacesbetween the pairs of plates on the axle a. The axles are mounted in aframe, which can be widely varied in its construction without affectingmy invention. In this instance the frame has at each side a hanger-plated, and these two plates are coupled together by means of a cross-bar e,and to the ends of said bar a pole A is attached by means of a yoke f,rigid on the pole, but pivoted at f to the ends of the bar. Upon therear end of the pole there is also a rigid forked orslotted arm providedwith a lateral bolt or pin g, and on the bar e there is a rigidsegmental plate h, which is provided with lateral holes h, and saidplate so occupies the fork 01' slot of whether plain or provided withteeth or the arm 9 that the pin or bolt g may be placed in any one ofsaid holes and thus enable the bar to be axially adjusted with relationto the pole and firmly secured in any one of the positions ofadjustment. hen the two axles occupy the same horizontal plane, bothsets of soil-working devices operate in the soil to an equal depth; butit will readily be seen that either set or gang may be more or lessraised and that the rear set may be wholly lifted from the surface ofthe ground and made to operate as a clearer for the other set fordetaching such weeds, roots, and balled soil therefrom as are liable tobe accumulated. The two axles are rotatively coupled, preferably bymeans of sprocket-wheelsz' and chain it, and in some cases chains shouldbe applied at both ends of the axles, and in others a single chain orother suitablegearing can be relied upon, and, as a rule, the chains orother gearing should be housed within a shieldingcover to prevent undueaccretion of obstructive matter. As here shown, the chain-gearin g isarranged to drive the rear set of soil-working devices at a higher speedthan the front set; but they may operate at uniform speed, or the rearset may be revolved slower than the front set without departure from myinvention. W'ith aharrow. thus organized both sets of soil-workingdevices may operate-With uniformity as to depth or either set adjustedto operate at a higher level than the other. Being geared together,should one set lag as to rotation, the other set will assist the first.Should one set only be needed for soil-working, the harrow can beadjusted, asin Fig. 3, the rear set then operating as a clearer, even ifnotgeared, because obstructive matter carried by the working set wouldbe presented to the overlying set and thereby detached. In this machinethe frame includes a crossbar (3; but the hanger-plates 'd are mountedupon but one axle a, and the rear axle b is coupled to the front axle bymeans of links or bars 61 Thevertical adjustment of the rear axle-iseifected by means of segrnentallyappropriate holes in the curved arms,as

clearly indicated.

It is to be understood that I do not restrict myself tothe use of anyspecial form of frame or; to particular means for rendering either ofasmuch as variations in such means could in no manner affect or vary thepractical working of both gangs upon the soil, or one gang as clearerstothe other.

It will be obvious that the character of the soil-working devices may bewidely varied withoutaffecting the main features of my invention, and.that with some forms of these devices it will be desirable that theaxles be inclined with reference to each other and to the line ofdraft-as, for instance, as shown in Fig. 4, wherein the soil-workingdevices are ed somewhat higher than the other. the axles geared togetherit will be seen that the well-known concavo-convex disks Z, these beingso arranged that the side thrust of one set will be substantiallybalanced by that of the other when both are operating at same depth inthe soil; but either set can be adjust- With neither gang is absolutelydependent for its rotation upon its own contact with the soil,

and therefore each may at times aid the other.-

disclosed in my Letters Patent No. 369,163,

the blades in this instance being bent or twisted at their outer ends.The rear axle b has a set of spiral-toothed wheels. These axles may begeared for securing uniform ro- 1 tation, as shown, or variably geared,it being obvious that in adapting my harrows for use in any particularkind of soil beset with any peculiar variety of weeds or grasses, itwill be important that the form of the soil-worki-ng devices, as well asthe relative rotation of the gangs, should be carefully considered forobtaining the most satisfactory results.

For meeting certain requirements my harrows need only be capable ofworking under two positions of adjustment-as, for instance,

as illustrated in Fig. 6, wherein the: crossbar e is bolted directly tothe rear end of. the

pole A, the bar having two holes at right anan elevated position andoperating as clearing devices for the other set. In this, simple form ofharrow the soil-working devices-willof course be varied to; meet localrequirements, and 1n some cases itwill be found advantageous, to employonly the front set for soil-working,.and at times the other set need notbe revolved at all, as when no clearing operation would be needed, as innon-adhef sive soils free from heavy weeds, &.c.

the revolving gangs vertically adjustable, in- 1 Among the many forms ofrevolvi'ngsoilworking devices which can be effectively employed in mybarrows is the one shown in Fig. 7, having round-pointed blades whichmay be either fiat or twisted. Another-(sho wn value only in harrowshaving the angularlyarranged axles. It will be obvious that the teeth,blades, or arms of the soil-working devices should as a rule be more orless twisted or alternately oifset, or bent in opposite directions, whenemployed on axles arranged at right angles to the line of draft,although when the front set is mainly relied upon for earth-working, andthe rear set revolved at a higher speed than the front set, the teeth ofthe rear devices may or may not be thus twisted or bent.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. In a harrow, the combination of a pole and a framerigidly adjustable with relation to each other, as by means of asegmental plate with holes, and a bolt or pin, and two front of theother, in the same path, the said frame being mounted upon the axles ofboth gangs, and capable according to adjustment of being carried whollyby the front gangaxle, or equally by both axles, substantially asdescribed.

2. In a harrow, the combination of a frame, a pole adjustable rigidlywith relation to said frame, and two gangs of rotative soil-workin gdevices which support said frame and the pole, and are geared together,as described, and adapted to operate together or separately, and atvariable depths in the soil.

GEORGE MARSHALL CLARK.

Witnesses:

ROBERT B. CLARKE, ROBERT S. ORUTTENDEN.-

gangs of rotative soil-Working devices, one in 20

